High velocity, rimfire cartridge

ABSTRACT

A .22 caliber rimfire cartridge includes a generally cylindrical casing having a rearward rimfire end and an opposing mouth end, wherein the rearward rimfire end has an annular rim connecting to a cylindrical casing portion extending to a casing forward edge and a bullet is disposed in the forward mouth end. In embodiments, the bullet comprises copper and a polymer binder. In embodiments, the bullet has a forward tapering portion with a central cavity, a first cylindrical portion with a first diameter and a cylindrical surface directly rearward of the tapering portion, a cylindrical driving band directly rearward of the first cylindrical portion, the cylindrical driving band having a second diameter greater than the first diameter and having an outer second cylindrical surface, a third cylindrical portion directly rearward of the cylindrical driving band, the third cylindrical portion having a third cylindrical surface with a diameter equal to the first diameter. In embodiments, the bullet is positioned with the third cylindrical surface mostly or entirely within the casing. In embodiments, the casing has a circumferential crimp positioned at the third circumferential portion. In embodiments, the third circumferential surface having a circumferential indentation at the circumferential crimp.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/841,261, filed Apr. 6, 2020 and claims the benefit of U.S.Provisional Application No. 62/830,333, filed Apr. 5, 2019, the entirecontents of each are incorporated by reference herein.

FIELD OF THE INVENTION

The present invention is directed to firearm cartridges for improvingsafety, reliability, and performance.

BACKGROUND OF THE INVENTION

In order to maintain their proficiency with various types of firearms,military personnel, law enforcement officers and hunters frequentlyengage in target practice. In the sport of hunting, marksmanship ispracticed so that a shot can be carefully placed to ensure a quick,clean and humane kill. For military personnel, good marksmanship maymake the difference between victory and defeat in battlefieldsituations. Target practice is often performed at a shooting range withseveral dozens or hundreds of cartridges being fired at each practicesession. The expense involved in firing so many rounds can be mitigatedby using a firearm that fires 22 caliber long rifle rimfire ammunition.22 caliber long rifle rimfire ammunition is extremely popular for targetshooting, plinking, and small game hunting due to its low cost andgenerally high performance. A vast array of handguns and rifles accept22 caliber long rifle rimfire ammunition, including single shot rifles,bolt action rifles, and semi-automatic rifles. Millions of 22 caliberrifles have been manufactured to use this ammunition.

Certain jurisdictions have restrictions in place or planned relating tolead ammunition. Lead-free bullets are known such as copper particlebullets with polymer binders.

SUMMARY OF THE INVENTION

In embodiments, a .22 caliber rimfire cartridge includes a generallycylindrical casing having a rearward rimfire end and an opposing mouthend, wherein the rearward rimfire end has an annular rim connecting to acylindrical casing portion extending to a casing forward edge and abullet is disposed in the forward mouth end. In embodiments, the bulletcomprises copper and a polymer binder. In embodiments, the bullet has aforward tapering portion with a central cavity, a first cylindricalportion with a first diameter and a cylindrical surface directlyrearward of the tapering portion, a cylindrical driving band directlyrearward of the first cylindrical portion, the cylindrical driving bandhaving a second diameter greater than the first diameter and having anouter second cylindrical surface, a third cylindrical portion directlyrearward of the cylindrical driving band, the third cylindrical portionhaving a third cylindrical surface with a diameter equal to the firstdiameter. In embodiments, the bullet is positioned with the thirdcylindrical surface mostly or entirely within the casing. Inembodiments, the casing has a circumferential crimp positioned at thethird circumferential portion. In embodiments, the third circumferentialsurface having a circumferential indentation at the circumferentialcrimp. In embodiments, rimfire cartridges have a leaded projectile orbullet without a jacket; or a jacketed projectile or bullet. Inembodiments, the bullet is composed of lead. In embodiments, the bulletcomprises a core and a jacket, wherein the jacket at least partiallysurround the core. In embodiments, the core composition is selected fromzinc, tin, lead, copper powder, and iron powder. In embodiments, thejacket composition is selected from copper, brass plated steel, brass,plated steel, and a polymer.

The above summary of the various representative embodiments of theinvention is not intended to describe each illustrated embodiment orevery implementation of the invention. Rather, the embodiments arechosen and described so that others skilled in the art can appreciateand understand the principles and practices of the invention. TheFigures in the detailed description that follow more particularlyexemplify these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be completely understood in consideration of thefollowing detailed description of various embodiments of the inventionin connection with the accompanying drawings, in which:

FIG. 1 is a perspective view showing a rimfire rifle and magazines forholding rimfire cartridges.

FIG. 2 is a side view of a rimfire cartridge.

FIG. 3 is a perspective view of a rimfire cartridge.

FIG. 4 is a side view of a rimfire cartridge.

FIG. 5 is a perspective view of a rimfire cartridge.

FIG. 6 is a side view of a rimfire cartridge, according to the priorart.

FIG. 7 is a side view of a rimfire cartridge, according to the priorart.

FIG. 8 is a stylized cross-sectional view showing a match chamber for arifle barrel, according to the prior art.

FIG. 9 is a stylized cross-sectional view showing a sporting chamber fora rifle barrel, according to the prior art.

FIG. 10 is a partial cross-sectional view showing a rimfire cartridgeincluding a casing and a projectile or bullet.

FIG. 11 is a side view showing a projectile or bullet.

FIG. 12A is a cross-sectional view showing a projectile or bullet.

FIG. 12B is a cross-sectional view showing a projectile or bullet.

FIG. 12C is a cross-sectional view showing a projectile or bullet.

FIG. 13 is a side view showing a projectile or bullet.

FIG. 14 is a cross-sectional view showing a projectile or bulletaccording to another embodiment.

FIG. 15 is a cross-sectional view showing a projectile or bulletaccording to another embodiment.

While the invention is amenable to various modifications and alternativeforms, specifics thereof have been depicted by way of example in thedrawings and will be described in detail. It should be understood,however, that the intention is not to limit the invention to theparticular embodiments described. On the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

Nonlead bullets with metal particles are significantly less dense thanlead bullets and therefore lighter such that similar sized non-leadbullets are capable of firing at greater velocities utilizing similarpropellant loads as cartridges with heavier lead bullets. Suchlightweight bullets are more rigid and accordingly do not deform asreadily as lead bullets. The inventors have determined that the lightweight metal and polymer bullets do not consistently obturate and sealas effectively as lead bullets in firearm barrels, and further that suchbullets do not secure in the mouths of casings as well as lead bullets.Moreover, the inventors have discovered that such cartridges withlightweight metal/polymer bullets, particularly copper particles inpolymer matrix, particularly 22 caliber cartridges, that are designed toprovide bullet kinetic energy comparable to high performance 22 caliberlead bullets, are highly sensitive to common variables involved inconventional cartridge manufacturing. Applicants have observed that suchsensitivity results in variable performance of cartridges, thevariability much worse than cartridges with lead bullets. Moreover,applicants have discovered that such variability is particularlyproblematic in firearms that utilize blow back from the cartridges forcycling the firearm, such as popular semi-automatic 22 caliber rifles.The variability in performance results in an unacceptable high scraprate of manufactured cartridges and/or jamming in semi-automatic 22caliber firearms.

A feature and advantage of embodiments is a cartridge having a crimpedportion that provides increase friction between the casing and theprojectile of the cartridge. A feature and advantage of embodiments is acartridge having a crimped portion that provides higher release pressureof a joint between the casing and the projectile of the cartridge.

A feature and advantage of embodiments is a cartridge 100 in which thecasing 102 and the projectile 114 are deformed to create an interlockingfeature thereby increasing bullet push and pull forces with or withoutthe addition of a case mouth crimp 126.

A feature and advantage of embodiments is a cartridge 100 havingincreased bullet push/pull forces that allow use of slower burningpropellants to provide minimal risk of partial ignitions resulting inoff sounds and high pressure/velocity ranges with lead-free light weight(<32 grains) bullets 114.

A feature and advantage of embodiments is a cartridge 100 containing aslower burning propellant, the cartridge 100 being configured togenerate sufficient gas pressure, upon ignition of the propellant, foroperation of a blow back reloading mechanism of a rimfire rifle orhandgun.

A feature and advantage of embodiments is a cartridge 100 having acrimped portion 126 that provides increase friction between the casing102 and the projectile 114 of the cartridge 100. In embodiments, abullet pull force required to separate the projectile 114 from thecasing 102 is greater than 70 lbs. In embodiments, a bullet pull forcerequired to separate the projectile 114 from the casing 102 is greaterthan 72 lbs. In embodiments, a bullet pull force required to separatethe projectile 114 from the casing 102 is greater than 75 lbs.

A feature and advantage of embodiments is a cartridge 100 having acrimped portion 126 that provides higher release pressure of a jointbetween the casing 102 and the projectile 114 of the cartridge 100.

A feature and advantage of embodiments is a cartridge 100 in which thecasing 102 and the projectile 114 are deformed to create an interlockingfeature thereby increasing bullet push and pull forces with or withoutthe addition of a case mouth crimp 126.

A feature and advantage of one or more embodiments is a projectile 114that addresses environmental concerns regarding lead by providing aprojectile 114 that is free of lead. A feature and advantage of one ormore embodiments is a lead-free projectile 114 having a driving band126.

A feature and advantage of embodiments is a cartridge 100 including alight weight lead-free projectile 114 weighing less than a leadprojectile of the same size (e.g., having the same body volume). Afeature and advantage of embodiments is a cartridge 100 includinglead-free projectile 114 having a weight less than 32 grains. A featureand advantage of embodiments is a cartridge 100 including lead-freeprojectile 114 having a weight less than 29 grains. A feature andadvantage of embodiments is a cartridge 100 including lead-freeprojectile 114 having a weight less than 26 grains. A feature andadvantage of embodiments is a cartridge 100 including lead-freeprojectile 114 having a weight less than 23 grains.

The inventors associated with the instant application have conceived ofa cartridge 100 having casing 102 that holds onto the projectile 114longer, even when the cartridge 100 is fired from a sporting chamberedrifle 20. In embodiments, the cartridge 100 allows a sporting rifle 20to perform more like a match rifle.

A feature and advantage of embodiments is a cartridge 100 including aretention mechanism that allows the cartridge casing to retain thecartridge projectile a fraction of a second longer than the samecartridge without the retention mechanism. Retaining the cartridgeprojectile a fraction of a second longer provides accuracy more likethat of a match chambered rifle when the cartridge is being used in asporting chambered rifle. A match chamber is typically used when maximumaccuracy is desired. With a rifle having a match chamber, cartridges aretypically individually loaded into the rifle (in other words,one-at-a-time). When each cartridge 100 is chambered, the projectile 114engages the rifling in the barrel. The engagement between the projectileand the rifling causes a match rifle hold onto the projectile longer,upon ignition of the propellant, relative to a rifle with a sportingchamber. In a sporting chambered rifle 20, on the other hand, there maybe a jump between the rifling and the chamber so that the projectiledoes not engage the rifling when a cartridge is chambered in thesporting rifle.

A sporting chamber may be used when a combination of convenience andaccuracy is desired. In embodiments, a sporting chambered rifle 20 maybe used in conjunction with removable magazines 134 that each hold aplurality of rimfire cartridges. The use of removable magazines 134allows a plurality of cartridges 100 to be easily loaded into thefirearm by inserting a single magazine 134 into the firearm. After eachcartridge 100 is fired, a manually or automatically operated mechanismmoves the bolt of the firearm backward and then forward again. The uppermost cartridge 100 in the magazine 134 is pulled off of a stack ofcartridges each time the mechanism cycles so that cartridges are fedone-by-one into the firing chamber of the firearm. Each magazinetypically has an elongate housing defining a chamber with aspring-loaded follower slidably disposed therein. The force of thespring-loaded follower urges each cartridge 100 in the magazine 134toward the upper most position in the where the bolt can push it intothe firing chamber. When all of the cartridges 100 have been fired, theempty magazine 134 is removed from the firearm and a new magazine 134 isinserted in its place. The empty magazine 134 may then be refilled withcartridges 100.

A feature and benefit of embodiments is a process for manufacturinglots/batches of cartridges 100, wherein the cartridges 100 of eachlot/batch exhibit more consistent ballistic characteristics when firedfrom sporting chambered rifle 20. In embodiments, the process provideslots/batches of cartridges 100 in which the cartridges 100 of eachlot/batch exhibit a mean velocity greater than 1145 fps and a velocitystandard deviation less than 145 fps when fired from a sportingchambered rifle 20. In embodiments, the process provides lots/batches ofcartridges 100 in which the cartridges 100 of each lot/batch exhibit anaverage pressure greater than 18,000 psi and a pressure standarddeviation less than 1000 psi when fired from a sporting chambered rifle20.

A feature and benefit of embodiments is a crimping process formanufacturing lots/batches of crimped cartridges 100, wherein thecrimped cartridges 100 of each lot/batch exhibit more consistentballistic characteristics when fired from sporting chambered rifle 20relative to un-crimped cartridges. In embodiments, the crimping processprovides lots/batches of cartridges 100 in which the crimped cartridgeshaving a crimped cartridge velocity standard deviation of a first valuewhen fired from a sporting chambered rifle. For comparison, a lot/batchof un-crimped cartridges have an un-crimped cartridge velocity standarddeviation of a second value when fired from a sporting chambered rifle.In embodiments, the ratio of the second value to the first value isgreater than 2.0. In embodiments, the ratio of the second value to thefirst value is greater than 1.5. In embodiments, the ratio of the secondvalue to the first value is greater than 2.5.

A feature and advantage of embodiments is a cartridge projectile havinga driving band portion and a bore riding nose portion. In embodiments,the bore riding nose portion has an outer diameter selected to provide asnug fit into a corresponding rifle bore when the cartridge is chamberedin the rifle. In certain embodiments, the diameter of the bore ridingnose portion is the same as the bore. In other embodiments, the diameterof the bore riding nose portion is slightly less than the diameter ofthe bore. In still further embodiments, the diameter of the bore ridingnose portion is slightly greater than the diameter of the bore. Inembodiments, the cartridge is dimensioned and configured so that thebore riding nose portion contacts the rifling inside the rifle barrelwhen the cartridge is chambered in the match chambered rifle. Inembodiments, the bore riding nose portion has an outer diameter selectedso that and resistance of the bore riding nose portion engaging therifling is easily overcome using force provided by the user's hands whenthe cartridge is chambered in the match chambered rifle having a boltaction and/or a single shot action. In embodiments, the cartridge isdimensioned and configured so that the bore riding nose portion does notcontact the rifling inside the rifle barrel when the cartridge ischambered in a sporting chambered rifle. In embodiments, the cartridgeis dimensioned and configured so that the driving band portion engagesthe rifling inside the rifle barrel after the cartridge is chambered ina sporting chambered rifle and the rifle is fired, igniting thecartridge propellant.

Certain embodiments herein are specifically addressed to projectilesfrom .15 caliber to .38 caliber. In embodiments, the cartridge has a .17caliber projectile. In embodiments, the cartridge has a .22 caliberprojectile.

In embodiments, rimfire cartridges have a lead-free projectile orbullet, a lead projectile or bullet; or a jacketed projectile or bullet.

Referring to FIGS. 1, 8 and 9, rimfire rifles may be configured with oneof a plurality of different chamber types. A match chamber (such as, forexample, a match chamber with the dimensions shown in FIG. 8) may beused when maximum accuracy is desired. A sporting chamber (such as, forexample, a sporting chamber with the dimensions shown in FIG. 9) may beused when a combination of convenience and accuracy is desired.Referring to FIG. 1, a sporting rifle 20 may be used in conjunction withremovable magazines that each hold a plurality of rimfire cartridges.The use of removable magazines allows a plurality of cartridges to beeasily loaded into the firearm by inserting a single magazine into thefirearm. After each cartridge is fired, a manually or automaticallyoperated mechanism moves the bolt of the firearm backward and thenforward again. The upper most cartridge in the magazine is pulled off ofa stack of cartridges each time the mechanism cycles so that cartridgesare fed one-by-one into the firing chamber of the firearm. Each magazinetypically has an elongate housing defining a chamber with a springloaded follower slidably disposed therein. The force of the springloaded follower urges each cartridge in the magazine toward the uppermost position in the where the bolt can push it into the firing chamber.When all of the cartridges have been fired, the empty magazine isremoved from the firearm and a new magazine is inserted in its place.The empty magazine may then be refilled with cartridges.

With a rifle having a match chamber, cartridges may be individuallyloaded into the rifle (in other words, one-at-a-time). When eachcartridge is chambered, the projectile engages the rifling in thebarrel. The engagement between the projectile and the rifling causes amatch rifle hold onto the projectile longer, upon ignition of thepropellant, relative to a rifle with a sporting chamber.

In a sporting rifle, there may be a jump between the rifling and thechamber so that the projectile does not engage the rifling when acartridge is chambered in the sporting rifle.

The inventors associated with the instant application have conceived ofa cartridge having casing that holds onto the projectile longer, evenwhen the cartridge is fired from a sporting rifle. In embodiments, thiscartridge allows a sporting rifle to perform more like a match rifle.

Referring to FIGS. 2, 3 and 10, in embodiments, a lead-free .22 caliberrimfire cartridge 100 includes a generally cylindrical casing 102 havinga rearward rimfire end 104 and an opposing mouth end 106, wherein therearward rimfire end 104 has an annular rim 108 connecting to acylindrical casing portion 110 extending to a casing forward edge 112and a lead-free bullet 114 is disposed in the forward mouth end 106. Inembodiments, the bullet 114 comprises copper and a polymer binder. Inembodiments, referring to FIG. 11, the bullet 114 has a forward taperingportion 116 with a central cavity 118, a first cylindrical portion 120with a first diameter D1 and a cylindrical surface directly rearward ofthe forward tapering portion 116, a cylindrical driving band 122directly rearward of the first cylindrical portion 120, the cylindricaldriving band 122 having a second diameter D2 greater than the firstdiameter D1 and having an outer second cylindrical surface, a thirdcylindrical portion 124 directly rearward of the cylindrical drivingband 122, the third cylindrical portion 124 having a third cylindricalsurface with a third diameter D3 equal to the first diameter D1. In someembodiments, the first cylindrical portion 120 is a bore riding noseportion. In embodiments, the bullet 114 is positioned with the thirdcylindrical portion 124 mostly or entirely within the casing 102. Inembodiments, the casing 102 has a circumferential crimp 126 positionedat the third cylindrical portion 124. In embodiments, the thirdcircumferential portion 124 has a circumferential indentation 128 at thecircumferential crimp 126.

Referring to FIGS. 10-13, in embodiments, a lead-free .22 caliberrimfire cartridge 100 comprises a generally cylindrical casing 102having a rearward rimfire end 104 and an opposing mouth end 106, whereinthe rearward rimfire end 104 has an annular rim 108 connecting to acylindrical casing portion 110 extending to a casing forward edge 112. Alead-free bullet 114 may be disposed in the forward mouth end 106. Inembodiments, the bullet 114 comprising copper and a polymer binder. Inembodiments, the bullet weighs 21 grains (plus or minus 2 grains). Inembodiments, referring to FIGS. 12A to 12C, the bullet 114 has a forwardor first cylindrical portion 120, a driving band 122 rearward of theforward or first cylindrical portion, and a rearward or thirdcylindrical portion 124 rearward of the driving band 122. Inembodiments, the bullet 114 has a center of mass and the driving bandpositioned rearward of the center of mass. In some embodiments, thediameter of the driving band is greater than the bore diameter. In otherembodiments, the diameter of the driving band is less than the diameterof the grooves or rifling in the bore or barrel. In embodiments, thebullet 114 is positioned with rearward or third cylindrical portion 124mostly within the casing 102. In embodiments, the casing 102 has acircumferential crimp 126 positioned at the rearward or thirdcylindrical portion 124 and the rearward or third cylindrical portion124 has a circumferential recess 128 at the circumferential crimp 126.In embodiments, the driving band 122 has a cylindrical surface with adiameter of 0.2240 inches (plus or minus 0.0010 inches), an axial lengthof 0.050 inches (plus or minus 0.010 inches), and a length of 0.410inches (plus or minus 0.020 inches). In embodiments, the driving band122 is position forwardly of the casing mouth end 106. In embodiments,the bullet 114 is positioned with the rearward or third cylindricalportion 124 at least 95% lengthwise within the casing 102.

Referring to FIGS. 6 and 7, by way of example, prior art cartridges nothaving crimps or driving bands are shown. In FIG. 6, a prior art leadcartridge has grooves that are not driving bands, but that help toreduce lead fouling. FIG. 7 shows a prior art 17 HMR cartridge.

Referring to FIG. 1, an upward direction U and a downward direction Dare illustrated using arrows labeled “U” and “D.” A forward direction Fand a rearward direction R are illustrated using arrows labeled “F” and“R,” respectively, in FIG. 1. A starboard direction S and a portdirection P are illustrated using arrows labeled “S” and “P,”respectively, in FIG. 1. In the embodiment of FIG. 1, these directionsmay be conceptualized from the point of view of a user who is holdingthe rifle 20. In embodiments, the rifle 20 may be used in conjunctionwith removable magazines that each hold a plurality of rimfirecartridges. The use of removable magazines may allow a plurality ofcartridges to be easily loaded into the firearm by inserting a singlemagazine into the firearm.

Referring to FIGS. 4 and 5, in embodiments a bottleneck rimfirecartridge 100 has casing 102, annular rim 108, crimp 126 and a jacketedprojectile or bullet having no driving band. In certain embodiments,such a cartridge may include a .17 caliber, mach 2 cartridge.

In embodiments, rimfire cartridges have a lead projectile or bulletwithout a jacket; or a jacketed projectile or bullet. For jacket-freelead projectiles or bullets, the projectile or bullet may appear thesame as bullet 114 of FIG. 10 and include a driving band 112. Likewise,the cartridge of this embodiment may include a casing 102 and crimp 126as shown in FIG. 10. In other embodiments, a lead bullet may not have adriving band, but may still include a casing 102 and crimp 126 as shownin FIG. 10.

Referring to FIG. 14, in embodiments, rimfire cartridges. may have aprojectile or bullet 114A with a core 130 and a jacket 132 whereinjacket 132 at least partially surrounds core 130. The cartridge of thisembodiment includes a casing 102 and crimp 126 as shown in FIG. 10. Inembodiments having jacketed projectiles or bullets, the core of theprojectiles or bullets may be selected from zinc, tin, lead, copperpowder, or iron powder. In embodiments having jacketed projectiles orbullets, the jacket may be selected from copper, brass plated steel,brass, plated steel, and a polymer.

Referring to FIG. 15, in embodiments, rimfire cartridges having ajacketed projectile or bullet 114B with a jacket 132 and a driving band126 are shown. The cartridge of this embodiment includes a casing 102and crimp 126 as shown in FIG. 10 and not shown in FIG. 14. The drivingband diameter of this jacketed embodiment may be larger and longer thanunjacketed embodiments depending on in-bore friction.

Various direction-indicating terms may be used herein as a convenientway to discuss the objects shown in the figures. It will be appreciatedthat many direction indicating terms are related to the instantorientation of the object being described. It will also be appreciatedthat the objects described herein may assume various orientationswithout deviating from the spirit and scope of this detaileddescription. Accordingly, direction-indicating terms such as “upwardly,”“downwardly,” “forwardly,” “backwardly,” “portly,” and “starboardly,”should not be interpreted to limit the scope of the invention recited inthe attached claims.

The following United States patents are hereby incorporated by referenceherein: U.S. Pat. Nos. 2,264,266, 2,286,064, 2,522,208, 2,765,558,2,777,235, 3,087,270, 3,577,860, U.S. Pat. Nos. 4,127,954, 4,566,212,4,580,364, 4,674,409, 4,672,760, 4,765,081, 4,776,122, 4,790,094,4,888,899, 5,216,199, 5,502,913, 6,352,033, 7,011,028, 7,493,862,8,407,922, 8,991,086, 5,301,449, 4,939,862, 4,739,572, 3,239,959, U.S.Ser. No. 10/234,221 and U.S. Ser. No. 10/240,879.

Components illustrated in the incorporated by reference references maybe utilized with embodiments herein. Incorporation by reference isdiscussed, for example, in MPEP section 2163.07(B). The above referencesto U.S. patents in all sections of this application are hereinincorporated by references in their entirety for all purposes.

All of the features disclosed, claimed, and incorporated by referenceherein, and all of the steps of any method or process so disclosed, maybe combined in any combination, except combinations where at least someof such features and/or steps are mutually exclusive. Each featuredisclosed in this specification may be replaced by alternative featuresserving the same, equivalent or similar purpose, unless expressly statedotherwise. Thus, unless expressly stated otherwise, each featuredisclosed is an example only of a generic series of equivalent orsimilar features. Inventive aspects of this disclosure are notrestricted to the details of the foregoing embodiments, but ratherextend to any novel embodiment, or any novel combination of embodiments,of the features presented in this disclosure, and to any novelembodiment, or any novel combination of embodiments, of the steps of anymethod or process so disclosed.

Although specific examples have been illustrated and described herein,it will be appreciated by those of ordinary skill in the art that anyarrangement calculated to achieve the same purpose could be substitutedfor the specific examples disclosed. This application is intended tocover adaptations or variations of the present subject matter.Therefore, it is intended that the invention be defined by the attachedclaims and their legal equivalents, as well as the illustrative aspects.The above described embodiments are merely descriptive of its principlesand are not to be considered limiting. Further modifications of theinvention herein disclosed will occur to those skilled in the respectivearts and all such modifications are deemed to be within the scope of theinventive aspects.

What is claimed is: 1-20. (canceled)
 21. A .22 caliber rimfire cartridgecomprising: a generally cylindrical casing comprising a rearward rimfireend and an opposing mouth end, wherein the rearward rimfire endcomprises an annular rim connecting to a cylindrical casing portionextending to a casing forward edge of the mouth end; a bullet disposedin the mouth end, the bullet comprising a first cylindrical portioncomprising a first diameter and a cylindrical surface, a driving banddirectly rearward of the first cylindrical portion, the driving bandcomprising a second cylindrical surface with a second diameter greaterthan the first, a third cylindrical portion directly rearward of thecylindrical driving band, the third cylindrical portion comprising athird cylindrical surface with a diameter less than the second diameter,wherein the bullet is positioned with the third cylindrical surfacewithin the casing, the casing comprising a first circumferential crimppositioned at the third circumferential portion and rearward of thecasing forward edge, the third circumferential surface comprising afirst circumferential indentation at the first circumferential crimp.22. The rimfire cartridge of claim 21, wherein the bullet is lead-free,comprises copper and a polymer binder, and comprises a weight of from 19to 23 grains.
 23. The rimfire cartridge of claim 21, wherein the casingforward edge comprises a second circumferential crimp and the thirdcircumferential surface comprises a second circumferential indentationat the second circumferential crimp and forward of the firstcircumferential crimp, and wherein the second circumferential crimpcomprises a rolled crimp at the mouth end.
 24. The rimfire cartridge ofclaim 21, wherein the bullet requires a pull force for separation fromthe casing of from 68 to 80 lbs.
 25. The rimfire cartridge of claim 21,the bullet further comprising a forward tapering portion with a centralcavity, wherein the cylindrical surface of the first cylindrical portionis directly rearward of the forward tapering portion.
 26. The rimfirecartridge of claim 25, wherein the bullet comprises a hollow point. 27.The rimfire cartridge of claim 21, wherein the driving band comprises achamfer surface comprising a chamfer of 150 degrees±10 degrees, theangle measured between the chamfer surface and the first cylindricalsurface.
 28. The rimfire cartridge of claim 21, wherein the driving bandcomprises a cylindrical surface with a diameter of 0.2240 inches±0.0010inches, and an axial length of 0.050 inches±0.010 inches, and a lengthof 0.410 inches±0.020 inches, the driving band positioned forwardly ofthe mouth end.
 29. The rimfire cartridge of claim 21, wherein the bulletis positioned with the third portion at least 95% lengthwise within thecasing.
 30. The rimfire cartridge of claim 21, wherein the seconddiameter of the driving band portion comprises a magnitude selected toprovide a snug fit into a corresponding rifle bore when the cartridge ischambered in a match chambered rifle.
 31. The rimfire cartridge of claim21, wherein the rimfire cartridge is dimensioned and configured so thatthe first cylindrical portion contacts rifling inside a rifle barrelwhen the cartridge is chambered in a match chambered rifle.
 32. Therimfire cartridge of claim 21, wherein the rimfire cartridge isdimensioned and configured so that the first cylindrical portion doesnot contact rifling inside a rifle barrel when the cartridge ischambered in a sporting chambered rifle.
 33. The rimfire cartridge ofclaim 21, wherein the second diameter of the driving band portioncomprises a magnitude selected so that the driving band portion engagesrifling inside a rifle barrel after the cartridge is chambered in asporting chambered rifle and the rifle is fired, igniting cartridgepropellant.
 34. The rimfire cartridge of claim 21, further comprising aslow burning propellant and a primer material disposed inside thecasing, the slow burning propellant comprising a first weight and afirst volume, the primer comprising a second weight and a second volume,wherein one or more of: a weight ratio of the first weight to the secondweight is less than 100, and a volume ratio of the first volume to thesecond volume is less than
 100. 35. The rimfire cartridge of claim 21,wherein the driving band is dimensioned and configured to engage riflinginside a rifle barrel after the cartridge is chambered in a rifle andthe rifle is fired igniting cartridge propellant and the firstcylindrical portion is dimensioned and configured to travel forwardlyalong the rifling inside rifle barrel after the cartridge is chamberedin a rifle and the rifle is fired igniting cartridge propellant.
 36. Arimfire cartridge comprising: a generally cylindrical casing comprisinga rearward rimfire end and an opposing mouth end, wherein the rearwardrimfire end comprises an annular rim connecting to a cylindrical casingportion extending to a casing forward edge of the mouth end; a bulletdisposed in the mouth end, the bullet comprising a forward taperingportion, a forward cylindrical portion comprising a first diameter and acylindrical surface directly rearward of the forward tapering portion, arearward portion rearward of the forward portion, wherein the bullet ispositioned with the rearward portion within the casing, the casingcomprising a circumferential crimp positioned at the rearward portionrearward of the casing forward edge, the rearward surface comprising acircumferential indentation at the circumferential crimp.
 37. Therimfire cartridge of claim 36, the bullet further comprising copper anda polymer binder, and the forward tapering portion of the bulletcomprises a central cavity, wherein the crimp is configured such thatthe cartridge requires a pull force for separation from the casing ofgreater than 70 lbs.
 38. The rimfire cartridge of claim 36, the bulletfurther comprising: the rearward portion comprising a rearward surfacewith a diameter equal to or less than the first diameter, and a drivingband rearward of the first cylindrical portion and forward of therearward portion, the driving band comprising a second cylindricalsurface with a second diameter greater than the first, and wherein thecasing forward edge comprises a forward circumferential crimp.
 39. Therimfire cartridge of claim 38, wherein the bullet comprises a core and ajacket, the jacket at least partially surrounding the core, wherein thecore composition is selected from zinc, tin, lead, copper powder, andiron powder, and wherein the jacket composition is selected from copper,brass plated steel, brass, plated steel, and a polymer.
 40. A rimfirecartridge comprising: a generally cylindrical casing comprising arearward rimfire end and an opposing mouth end, wherein the rearwardrimfire end comprises an annular rim and the mouth end comprises acasing forward edge; a bullet disposed in the mouth end, the bulletcomprising a forward cylindrical portion comprising a forward surface, arearward cylindrical portion rearward of the forward portion, therearward cylindrical portion comprising a rearward surface, wherein thebullet is positioned with the rearward surface within the casing, thecasing forward edge comprising a first circumferential crimp, and thecasing comprising a second circumferential crimp positioned at therearward cylindrical portion rearward of the casing forward edge, thethird surface comprising a circumferential indentation at the secondcircumferential crimp.